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Our Atmosphere

Our Atmosphere. The envelope of gasses that surrounds our planet. Atmospheric Composition. Our “air” is made up of: -78 % Nitrogen -21 % Oxygen -0-4 % Water Vapor -0.93 % Argon -0.038 % Carbon Dioxide -0.01 % Trace Gases

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Our Atmosphere

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  1. OurAtmosphere The envelope of gasses that surrounds our planet.

  2. Atmospheric Composition Our “air” is made up of: -78% Nitrogen -21% Oxygen -0-4% Water Vapor -0.93% Argon -0.038% Carbon Dioxide-0.01% Trace Gases Carbon dioxide has increased from 0.028% over the past 150 years. Why might this be significant? Our atmosphere from space

  3. A special component of our atmosphere - Ozone -Ozone molecules help to protect us from the suns harmful UV radiation. The ozone molecule (O3) is created naturally in our atmosphere when typical oxygen molecules (O2) gain an extra oxygen atom.

  4. Last/Outer Layer of our Atmosphere Layers of the Atmosphere: Exosphere- the traditional boundary between Earth’s atmosphere and outer space. Thermosphere: The layer has extremely low density which causes the temperature, temp is more than 1000°C. This layer also contains the Aurora from solar wind! Mesosphere: This layer actually decreases in temperature. This is the layer that protects us from meteoroids! Stratosphere- Here temperature increases with altitude, especially in the Ozone Layer. The UV absorption of UV radiation in the ozone causes the temperature to rise. The OZONE layer protects humans from the extremely dangerous UV waves from the Sun. Troposphere – The layer we live in. All weather happens here. Temps can be as low as -60°C. Tropopause Tropopause Tropopause Atmospheric Layers Surface of Earth

  5. Air Pressure is the weight of the air pressing down on you. • Air Pressure and Elevation- As you go higher in elevation, the air molecules are more spread out, therefore the air is less dense. Also, there is less air above you being pulled down on you by gravity. • Air pressure and Weather: Sunny Weather= High Pressure (approx. the weight of a school bus!) Cloudy/Rainy Weather = Low Pressure (approx. the weight of a Volkswagen beetle) Why don’t humans crush if we are always under such extreme pressure? Air Pressure Air Pressure is measured with a barometer, in millibars (mb)

  6. Imagine a closed container with a fixed amount of gas….. -Air pressure and temperature: As temperature increases, so does pressure due to the increased rate of movement of the gas particles. -Air pressure and density: As air pressureincreases, so does density because more molecules are being crammed into a given space. -Temperature and density: As temperature increases, molecules get more energized and spread out decreasing density. Pressure-temperature-density relationship:

  7. Heat Transfers- The way heat is exchanged on Earth. Radiation: The direct transfer of heat through the air. Examples: sunlight, heat given off from a fire or stove Conduction: The transfer of heat from one object to another. Example: heat from the hot pot directly to your hand, the pot directly heating the water. Convection: The circulation of heat through a liquid or gas. Example: warm air rising, a boiling pot of water circulating, lava lamp. Why does warm air rise?

  8. These inversions occur as land cools very quickly and cold air gets trapped under warm air. In highly populated areas, this can become a problem because pollution can get trapped in the cold air near Earth’s surface. Temperature inversions An increase in temperature with height in an atmospheric layer. Normally, an increase in height decrease causes a decrease in temperature.

  9. WIND – 2 types: local and global -All winds are caused by pressure differences between to masses of air. The air always tends to flow from high pressure (or density) to low pressure (or density) just like carbonation escaping a freshly opened bottle of soda). These pressure differences are caused by the unequal heating of Earth’s surface. Local wind: These are short term winds that move over small distances and change from day to day or even hour to hour. (This is what you typically think of when you think of wind)

  10. Global Winds: These are long-term movements in Earth’s atmosphere that travel long distances and always in the same direction. Think about temperature differences (compare the equator and the poles) and why these winds are always moving in the same direction.

  11. Coriolis Effect • Coriolis Effect is the curving of winds and ocean currents due to the very fast rotation of the Earth. • Therefore, winds will not travel in a straight line, they will curve. • This effect also causes storms such as hurricanes to rotate clockwise in the northern hemisphere and counter clockwise in the southern hemisphere.

  12. Land Breeze Occurs during the evening Land cools off yet water holds heat Wind blows from land to sea Sea Breeze Occurs during the day Land heats up quickly due to sunlight and water takes longer to heat up Wind blows from see to land Land and Sea breezes

  13. Mountain Influence: • Leeward side of a mountain • The DRY side • Usually a desert • Rain shadow is an area of little to no rain • Windward side of a mountain • The WET side • Warm moist air raises off the ocean • Clouds and precipitation form • Mountains block the moisture from heading over the mountain • Usually a temperate or rainforest Rainforest Desert Influence of topography

  14. Humidity – The amount of water vapor in the atmosphere at a given time. -Saturation: when the amount of water vapor in the air has reached its maximum amount. -Relative Humidity: The amount of water vapor in a volume of air relative to the amount of water vapor needed for that volume of air to reach its saturation point. For example, any saturated volume of air has 100% relative humidity. If the air only contains half of the water vapor needed for it to be saturated, it has a relative humidity of 50%.

  15. Cirrus tell that there will be a storm in a couple of days These are the only vertical clouds and are the huge thunderstorm and tornado clouds. Fair sunny weather Rain but not thunderstorms Flat/Low overcast clouds Dew point is the temperature at which the air can no longer hold all of its water vapor, and that vapor begins to condense into liquid water.

  16. CLOUD NAMES Precipitation Shape -Cirrus means curly or thin. -Stratus means layered. -Cumulus means lumpy or piled up. Clouds containing precipitation will have the word Nimbsomewhere in the name. Height -Cirro are clouds above 6,250 meters. -Alto clouds are between 1,875 and 6,250 meters. -There is no prefix for clouds below 1,875 meters.

  17. Cloud Formation-clouds form by tiny water droplets attaching to dust particles in the sky. Eventually the drops will build up on the dust until it becomes heavy enough for gravity to pull it to the Earth’s surface as precipitation. • Evaporation fills the air with water vapor (gaseous water) • Air rises away from the surface, carrying the moisture upward. • As it rises, the temperature drops causing the water vapor to condense into tiny droplets. • Water molecules attach to condensation nuclei (tiny dust particles that cloud droplets form around). • Coalescence - The droplets continue to grow in size as condensation continues. Most droplets will eventually collide with another droplet, increasing size. • Once they become heavy enough, gravity will pull them to the ground as precipitation. Cloud Formation Time Lapse

  18. Types of Precipitation • Rain- liquid precipitation • Sleet- frozen ice pellets (less than 5mm) • Freezing Rain- comes down as a liquid by freezes on contact leaving a glaze of ice. • Snow- frozen, six-sided crystals. • Hail- (only forms in cumulonimbus clouds) ice pellets that circulates vertically in the clouds and forms layers as it grows bigger. Supercooling – The process by which a substance drops below its freezing point without turning into a solid. http://dsc.discovery.com/search/results.html?query=hail

  19. The Water Cycle

  20. Air Masses: Weather for each air Mass: cP- Continental Polar: Clear and cool mP- Maritime Polar- Cool with rain or snow A- Arctic- Extremely cold and dry cT- Continental Tropical- Hot and dry (summer only and never reaches NJ) mT- Maritime Polar- warmer than usually with precipitation An air mass is a body of air that carries the characteristics from where it forms. If it formed over water, it brings moisture. If it formed over land, it is dry. The air masses are carried across the US by the Prevailing Westerlies. Therefore, your weather comes from the west.

  21. Fronts- The boundary at the front of an air mass The front created depends on the characteristics of the air mass.. Cold Front – Cold air moves in, forcing warm air up. Intense precipitation and storms are common with cold fronts. Warm Front – Warm air moves in, displacing the cold air. The warm air rises gradually causing widespread light precip. Stationary Front – When 2 air masses meet but neither advances. They are usually similar in temperature. Causes cloudy weather with light winds and occasional precipitation. Occluded Front – When a cold front catches up to and takes over a warm front. Warm air is forced up violently. Typically causes strong winds and heavy precipitation. http://www.physicalgeography.net/fundamentals/7r.html

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